Electricity Flashcards
Enlightenment period
1730-1790
Priestly and electricity
claims if you master the matter, your status rises
acknowledged that it is very useful for impressing others
when did study of electricity start properly?
2nd half of 18th c.
What were they more interested in in 17th c.
magnetism- looked at attractive and repulsive properties
How were theories in electricity developed?
as a result of observation of new phenomena after creating equipment to demonstrate to public
Air pump made by
Robert Boyle in 1660’s
actually made by Robert Hooke=poor and “invisible assistants”
What is an air pump
large glass globe which can be evacuated, forming a vacuum
What was Boyle famous for?
Advances in chem, air pump
Praised for religious commitment by peers
Why could Boyle do experiments?
had enough money to do whatever he wanted- did it out of interest & curiosity
What did Boyle do with the airpump?
Placed barometers inside to prove a vacuum had been made
What was everyone interested during 18th c.
Phosphorescence- glowing things
Barometric glow
purple light seen above mercury after barometer is shaken
Used as theatrical demonstration at Royal Society
Francis Hauksbee
Experimental assistant at Royal Society
-created demonstrations to show to fellows every week, so he could improve the design of the air pump
What did Hauksbee achieve?
Could produce a ‘shower of fire’ by passing air through mercury in a vacuum
Then discovered glow could be achieved by rubbing objects together in the globe
Hauksbee’s new machine
Glass globe mounted on spindle, then when hand placed on it, bright purple light produced
What were the scientific advances from the electrical machine?
Newton spotted it was linked with electricity
But Hauksbee didn’t realise significance and died a few years later
Stephen Gray
Learned about spinning globe from Philosophical Transactions (published by RS)
Made fellow of RS in 1730
What did Gray achieve?
Saw feathers were attracted to corks at either end of electric tube- electrical charge can be transmitted
Demonstrated to RS, but theoretical background ignored
Electrical machine used around Europe
Device altered, but performers and people studying theory were the same. So not much progress made
Benjamin Rackstrow
Replicated ‘Beatification’ using electric machine- make a crown of light around someone’s head by electrocution
Natural Philosophers’ opinion of electrical performances
disagreed with financial gain involved, but ended up joining in as needed to fund their own research
Leyden Jar function
creates larger charges and can store them
How was the leyden jar made
trial and error experiments
-Pieter van Musschenbroek accidentally made huge electric shock, then told colleague how to make ita
How leyden jar works
metal rod touching spinning glass jar and dips into glass with water, charge stored
To be electrocuted must touch jar and rod
Popularity of leyden jar
people flocked and paid money to experience electrocution
Adam Walker did what
used electrical experiments to demonstrate theoretical concepts & engage audience
What was going on by the end of the century
proper experiments with proper equipment to find out what’s going on eg Coulomb
What experiments did Coulomb do?
Torsion balance to show Newton’s inverse square law can be applied to electricity
What experiments did Cavendish do?
created a ‘torpedo’ to replicate effects of electric fish, did maths to work out numbers
